Summer is here and many of you may be considering the idea of drilling a bore well, especially those dwelling in urban areas and in large gated communities, to meet the increased demand due to shortage of water. Here are a few points which may help you understand the process better.
- Identification of Suitable site for drilling: One of the most common methods used for domestic bore well drilling is Vertical Electrical Sounding, for which large open area is required. Traditional methods used by local diviners using wood sticks/magnetic blocks are also successful to an extent.
- Dimensions : 6 inches diameter bore well are usually drilled for large apartments , while initially larger diameter bits are using for drilling so as to place the casing pipes.
- Determining yield while drilling : Generally a metal plate or wooden board with a V shape slot , called the V-notch is used to determine the yield during the process of drilling.
- Calculating water level in well from ground : Count the number of seconds it takes for a small stone dropped into well to hit the water and multiply by 9.8 ( result is in meters) Repeat this a few times to calculate accurately.
- Drinking quality of water in bore : Testing a sample of the water at a lab for iron, fluoride, TDS, arsenic and nitrate , bacterial growth, suspended particles and comparing them with IS Code 10500:1991 can help you determine pot ability of the water.
- Type of pump : For depths up to 150 feet Jet pumps are sufficient, while the best suited pumps are submerged centrifugal pumps
- In case of space constraints, portable flexible rigs can be used but only up to a depth of 300 feet.
- PVC casing pipes should adhere to IS 12818: 1992 which covers detailed requirements plain , ribbed screen and plain screen casing pipes of diameter 40 to 400 mm made of un-plasticized PVC.
- Casing pipes need to installed at the depth where water is finally struck to prevent silt from entering the well which may end up jamming the pump.
- Charges of drilling a bore well include Charges for drilling a specified size of bore well include , drilling cost per feet + cost of casing pipe per feet +installation charge for casing pipe per feet + flushing charges per hour after drilling + transportation charges
It is of utmost importance that before drilling a bore well, valid permission needs to be obtained from the local governing bodies and also extremely important to safely close shut a defunct bore well.
